Reamer with replaceable cutting blade

ABSTRACT

The cutter head of a reamer has a groove shaped for receiving a cutting blade which partly separates an integral jaw portion from the remainder of the cutting head. A clamping screw permits the jaw portion to be tightened on the cutting blade whose mobility is increased by a slot in a plane intersecting the groove at an obtuse angle. Further slots may be provided for distributing the pressure of the jaw portion on the blade in a desired manner.

United States Patent 1 1 3,591,305

[72} Inventors Johann Aichhorn [56] References Cited Ade; UNITED STATES PATENTS lfig zzj fiz i 2,561,470 7/1951 Hadley et a1 144 229 21] A pl No 814159 y 3,367,007 2/1968 Ziegler I 29/105 [22] i 7 1969 3,490,315 1/1970 Melchiorre 77/75 [45] patented July 1,364,346 1/1921 Adams 144/230 [73] Assignee Mapal Dr. Kress K.G. Primary Examiner-Franeis S. Husar Aalen, Germany Attorney-Kelman and Berman 32 Priority Apr. 111, 1968 [33] Germany 1 [31] P1752 151.6

[54] REAMER WITH REPLACEABLE CUTTING BLADE ABSTRACT: The cutter head ofa reamer has agroove shaped for receiving a cutting blade which partly separates an integral Claims 9 Drawing Figs jaw portion from the remainder of the cutting head. A clamp- [52] US. Cl 408/161, ing screw permits the jaw portion to be tightened on the 29/105 R, 1 4/2 1 4/ 408/240 cutting blade whose mobility is increased by a slot in a plane [51] Int. Cl 823d 77/00 intersecting the groove at an obtuse angle. Further slots may Field of Search 7 7/58.3, b provided for distributing the pressure'of the jaw portion on 1 29/105 the blade in a desired manner.

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REAMIIIR WITIII REPLACIEABLE CUTTING BLADE BACKGROUND OF THE INVENTION This invention relates to reamers, and particularly to a reamer equipped with a cutting blade replaceably arranged in a cutter head of the reamer, and more specifically with improvements in the clamping of the blade to the head.

In known reamers of the type with the improvement of which this invention is concerned, a jaw portion is separated from the integral remainder of the cutting head by a groove elongated in the direction of the axis of reamer rotation, and a clamping screw connects the jaw portion to the remainder of the head for clamping the jaw portion against the wide face of the blade which is the leading radial face of the blade during normal reamer operation.

The known clamping devices do not adequately fix the positions of all parts of the cutting edge on the blade relative to the axis of rotation of the reamer or relative to any other fixed reference line on the stationary machine structure. If the blade is tightly clamped only near its axially central position, shallow corrugations may be produced in the machined workpiece by oscillation of the relatively loose outer portion of the blade. If the blade is not safely prevented from pivoting in an axial plane, even more serious defects may occur in the workpiece.

The primary object of the invention is the provision of a cutter head of the type described in which a replaceable blade is firmly and uniformly fastened over its entire axial length and cannot tilt in an axial plane under the stresses to which it is normally exposed during reamer operation.

SUMMARY OF THE INVENTION With this object and others in view, as will hereinafter become apparent, the cutter head of the invention is provided with a slot which defines a plane offset from the plane defined by the blade receiving groove, both planes extending in the direction of the axis of reamer rotation. A portion of the slot directly communicates with the groove so that the slot further separates the jaw portion from the remainder of the cutter head.

When the slot extends away from the groove and has a concavely arcuate bottom wall remote from the groove, the jaw portion is resiliently attached to the remainder of the cutter head by integral bridges so shaped as to cause all axial portions of the jaw face in the blade-receiving groove to move in unison when the central part of the jaw portion is drawn against the blade by one or more clamping screws.

Other features, additional objects, and many of the attendant advantages of this invention will readily become apparent from the following detailed description of preferred embodimerits when considered in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. I shows a reamer of the invention in fragmentary side elevation;

FIGS. 2 and 3, show the reamer of FIG. 1 in radial section on the lines II-II and III-III respectively;

FIG. 4 illustrates another reamer of the invention in a view corresponding to that of FIG. 1;

FIGS. 5 and 6 are radially sectional views of the reamer of FIG. 4 in section on the lines V-V and Vl-VI respectively;

FIG. 7 shows yet another reamer of the invention in fragmentary side elevation; and

FIGS. 8 and 9 show the device of FIG. 7 in respective sections on the lines VIII-VIII and IX-IX.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to FIGS. l to 3, there is seen only one axially terminal portion of a reamer shank which carries the cutter head I of the reamer. A groove 2 in the head nonnally receives a cutting blade 3 and separates an integral clamping jaw 4 from the remainder of the head I which is a unitary piece of metal and, in the embodiment: of FIGS. I to 3, unitary with the shank 20.

The groove 2 is axially elongated and defines a plane which is parallel to the axis of reamer rotation. A narrow slot 5 extends into the solid material of the head I from the groove 2 near the bottom wall of the same in an axial plane offset from the aforementioned plane defined by the groove 2 at an obtuse angle of about It cuts into the material of the head I so as further to separate the jaw 4 from the remainder of the head I. The bottom wall 6 of the slot 5 intersects the plane of the slot in a concave, circular arc as is best seen in FIG. 2. The cutter head I shown in FIGS. I to 3 being relatively slim, the curved bottom wall 6 axially closes the rear end of the slot 5 and almost completely closes the front end of the slot in an axial direction.

The jaw 4 is clamped against the blade 3 in the groove 2 by two clamping screws 7 threadedly received in corresponding bores of the jaw 4 and rotatable in smooth bores in the remainder of the head I. The lentil heads of the screws 7 are recessed in conically flaring orifices of the bores and provided with hexagonal recesses for insertion of a conforming key. The screws 7 pass almost at right angles through the plane of the slot 5 near the deepest portion of the slot.

Two adjusting screws 8 without heads are axially offset from the screws 7 in opposite directions and are thus located almost entirely in the solid portion of the cutter head. The parallel axes of the two adjusting screws are almost parallel to the plane of the slot 5, and they define a plane parallel to the axis of the reamer rotation which is transverse, though not precisely perpendicular, to the corresponding plane defined by the axes of the screws 7, as is evident from joint consideration of FIGS. 2 and 3.

An adjusting wedge 9 is associated with each screw 8 in axial alignment and extends into the groove 2 for holding the blade 3 in a desired position. When the jaw 4 is clamped fast against the leading radial face of the blade 3 exposed in the relief I0, the wedge 9 is also fixed in position, and the two wedges located near the axial ends of the blade 3 jointly prevent tilting of the blade in the plane defined by the groove 2.

Shallow axial grooves in the outer face of the cutter head 1 receive partly projecting guide bars 112.

When the clamping screws 7 are tightened to elastically deflect the jaw 4, the pressure of the clamping jaw 4 on the blade has been found to be practically uniform over the entire axial length of the clamping face on the jaw 41, and not tilting of the blade in an axial plane has been observed under even severe machining stresses. The described angular relationship of the planes defined by the groove 2 and by the slot 5 provides adequate mobility of the jaw portion without permitting the jaw to yield under the working stresses. The small width of the slot portion contiguously adjacent the recess 2 and its location near the bottom wall of the groove are beneficial in not significantly reducing the area of the jaw face engaging the blade 3.

The transverse orientation of the axes of the screws 7, 8 causes the adjusting screws 8 and their associated wedges 9 to be fixedly fastened in the adjusted position when the clamping screws 7 are tightened.

As has been pointed out above, the cutter head I is relatively slim, its diameter being less than 50 percent greater than that of the associated shank, the the diameter of the latter being deten'nined by the available, nonillustrated chuck of the machine. When holes of relatively large diameter are to be enlarged, correspondingly large reamer heads must be used, and a single slot 5 cannot provide the resiIient mobility of a jaw portion discussed above. The two embodiments of the invention shown in FIGS. 4 to 9 indicate the manner in which the basic features described above may be utilized under such conditions.

Referring initially to FIGS. 4 to 6, there is seen a reamer whose cutter head diameter is more than twice that of the associated shank 20. The groove 2 in the head I and the blade 3 held therein are practically identical in their dimensions with the corresponding features seen in FIGS. l to 3, and the bottom of the groove 2 communicates with a slot similar to the corresponding slot in the first-described embodiment. The bridge of solid metal connecting the jaw portion 4' with the remainder of the head 1 could not be flexed in the desired manner by clamping screws 7' without further reduction of its effective cross section.

Another slot 13 extends inward of the head 1' from the outer cylindrical surface of the same in a plane which is approximately perpendicular to the plane of the slot 5, and the bottom wall of the slot 13 intersects the plane of the last-mentioned slot in a concave circular are best seen in FIG. 4. The portion of the slot 13 farthest from the head surface directly communicates with that portion of the slot 5 which is near the bottom wall 6' of the latter and farthest from the groove 2. The axially central part of the jaw portion 4 is thus completely severed from the remainder of the head in the radial plane of FIG. 5. The adjusting screws 8' are oriented relative to the screws 7' in a manner more fully discussed above, and differ from the aforedescribed screws 8 in their length only. They back wedges 9' of suitably adjusted dimensions. The cutting head 1 is recessed to provide a relief 10 and grooves for receiving guide bars 12 as described above.

In order further to enhance the mobility of the jaw portion 4', the slot 5 is open in an axially forward direction over about three-fourths of its greatest depth to the bottom wall 6.

The reamer seen in FIGS. 7 to 9 differs from that shown in FIGS. 4 to 6 by a cutter head 1 mounted on a tubular shank by a press fit. Its cutting blade 3 is partly exposed in a relief 10. A slot 5 is provided as described above. lts dimensions are substantially as shown in FIGS. 1 and 3, and the solid bridge between the portions of the head 1" on either side of the blade 3 is radially relatively thin because of a central bore 19 in the cutter head. The efiectiveness of the clamping screws 7' is further enhanced by two radial slots 11 axially adjacent the screws 7 which define therebetween a clamping tongue 4" threadedly engaged by the screws 7.

As is seen from FIG. 7, the tongue 41" engages the blade 3 over approximately one-half of its axial length, and the adjusting screws 8 and associated wedges 9 hold the axially terminal blade portions in position.

The slots 11 have circularly arcuate bottom walls for the reasons described above. The slots 11 directly communicate with the central bore 19 to provide adequate resiliency to the tongue 4". The reamer shown in FIGS. 7 to 9 is otherwise closely similar to that described with reference to FIGS. 4 to 6, and identical elements have been provided with corresponding reference numerals.

What we claim is:

1. In a reamer including a shank (20) having an axis of rotation, and a cutter head (l) on an axially terminal portion of said shank, said cutterhead being formed with an elongated groove (2) shaped for receiving a cutting blade (3), said groove defining a first plane extending in the direction of said axis and partly separating an integral jaw portion (4) from the remainder of said head, and clamping means (7) for pressing a face of said jaw portion against a cutting blade received in said groove, the improvement which comprises a slot (5) in said head defining a second plane offset from said first plane and extending in the direction of said axis, a portion of said slot directly communicating with said groove and further separating said jaw portion from said remainder of the head, the axially terminal portion of said slot remote from said shank being substantially closed by a bridge integrally connecting said jaw with said remainder.

2. In a reamer as set forth in claim 1, said slot extending in a direction away from said groove and having a bottom wall remote from said groove and intersecting said second plane in a concave arc. I

3. ln a reamer as set forth in claim 2, said first and second planes intersecting each other at an obtuse angle.

4. In a reamer as set forth in claim 3, said slot being much narrower than said groove.

5. In a reamer as set forth in claim 3, said slot being substantially closed in both axial directions.

6. In a reamer as set forth in claim 1, said head being formed with another slot (13) defining a third plane intersecting said second plane and extending in the direction of said axis, said other slot communicating with said first-mentioned slot within said cutter head and further separating said jaw portion from said remainder of the head.

7. In a reamer as set forth in claim 1, said jaw portion being formed with two additional slots extending in respective axially spaced planes transverse to said axis of rotation from an outer surface of said jaw portion to said groove and to said first-mentioned slot so as partly to separate a clamping tongue axially extending between said two additional slots from axially adjacent parts of said jaw portion.

8. In a reamer as set forth in claim 7, said additional slots having respective bottom walls remote from said outer surface and intersecting the respective axially spaced planes in concave arcs.

9. In a reamer as set forth in claim 1, said clamping means including a clamping screw connecting said jaw portion and said remainder and threadedly engaging one of said jaw portion and of said remainder, said clamping screw having an axis extending in a plane transverse to said axis of rotation, and defining a plane parallel to said axis of rotation; and adjusting screw means (8,9) threadedly received in said head for threaded movement about an axis extending in a plane transverse to said axis of rotation and spaced from said clamping screw in the direction of said axis of rotation, the adjusting screw means extending into said groove for adjusting engagement with a blade received in said groove, the axis of said threaded movement defining a plane parallel to said axis of rotation and transverse to the plane parallel to said axis of rotation defined by the axis of said clamping screw.

10. In a reamer as set forth in claim 4, the depth of said slot away from said groove increasing from said axially terminal portion of said slot toward the axially central portion, said jaw portion and said remainder jointly constituting a unitary piece of metal. 

1. In a reamer including a shank (20) having an axis of rotation, and a cutter head (1) on an axially terminal portion of said shank, said cutterhead being formed with an elongated groove (2) shaped for receiving a cutting blade (3), said groove defining a first plane extending in the direction of said axis and partly separating an integral jaw portion (4) from the remainder of said head, and clamping means (7) for pressing a face of said jaw portion against a cutting blade received in said groove, the improvement which comprises a slot (5) in said head defining a second plane offset from said first plane and extending in the direction of said axis, a portion of said slot directly communicating with said groove and further separating said jaw portion from said remainder of the head, the axially terminal portion of said slot remote from said shank being substantially closed by a bridge integrally connecting said jaw with said remainder.
 2. In a reamer as set forth in claim 1, said slot extending in a direction away from said groove and having a bottom wall remote from said groove and intersecting said second plane in a concave arc.
 3. In a reamer as set forth in claim 2, said first and second planes intersecting each other at an obtuse angle.
 4. In a reamer as set forth in claim 3, said slot being much narrower than said groove.
 5. In a reamer as set forth in claim 3, said slot being substantially closed in both axial directions.
 6. In a reamer as set forth in claim 1, said head being formed with another slot (13) defining a third plane intersecting said second plane and extending in the direction of said axis, said other slot communicating with said first-mentioned slot within said cutter head and further separating said jaw portion from said remainder of the head.
 7. In a reamer as set forth in claim 1, said jaw portion being formed with two additional slots extending in respective axially spaced planes transverse to said axis of rotation from an outer surface of said jaw portion to said groove and to said first-mentioned slot so as partly to separate a clamping tongue axially extending between said two additional slots from axially adjacent parts of said jaw portion.
 8. In a reamer as set forth in claim 7, said additional slots having respective bottom walls remote from said outer surface and intersecting the respective axially spaced planes in concave arcs.
 9. In a reamer as set forth in claim 1, said clamping means including a clamping screw connecting said jaw portion and said remainder and threadedly engaging one of said jaw portion and of said remainder, said clamping screw having an axis extending in a plane transverse to said axis of rotation, and defining a plane parallel to said axis of rotation; and adjusting screw means (8, 9) threadedly received in said head for threaded movement about an axis extending in a plane transverse to said axis of rotation and spaced from said clamping screw in the direction of said axis of rotation, the adjusting screw means extending into said groove for adjusting engagement with a blade received in said groove, the axis of said threaded movement defining a plane parallel to said axis of rotation and transverse to the plane parallel to said axis of rotation defined by the axis of said clamping screw.
 10. In a reamer as set forth in claim 4, the depth of said slot away from said groove increasing from said axially terminal portion of said slot toward the axially central portion, said jaw portion and said remainder jointly constituting a unitary piece of metal. 